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Effects of tyrosine kinase inhibitors on the proliferation of human breast cancer cell lines and proteins important in the RAS signaling pathway
Author(s) -
Clark Jeffrey W.,
SantosMoore Anabela,
Stevenson Lisa E.,
Frackelton A. Raymond
Publication year - 1996
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/(sici)1097-0215(19960117)65:2<186::aid-ijc10>3.0.co;2-c
Subject(s) - receptor tyrosine kinase , tyrosine kinase , cancer research , proto oncogene tyrosine protein kinase src , platelet derived growth factor receptor , signal transduction , biology , tyrosine phosphorylation , growth factor receptor , ror1 , microbiology and biotechnology , tropomyosin receptor kinase c , biochemistry , receptor , growth factor
Breast cancers frequently over‐express a number of growth factor receptors. In addition, elevated src family kinase activity is present in a percentage of these neoplasms and has been implicated in signal transduction in these cells. Therefore, inhibiting tyrosine kinase activity is a potential approach for treating these tumors. Utilizing the SKBR3 and MCF‐7 breast cancer cell lines, we evaluated the effects of broadly targeting growth factor receptor and cytoplasmic tyrosine kinases with tyrosine kinase inhibitors (herbimycin A and genistein) to inhibit proliferation. We also evaluated these inhibitors' effects on proteins that regulate ras function, which is a convergence point for signaling through both src family kinases and a number of growth factor receptors with tyrosine kinase activity (e.g., epidermal growth factor and erbB‐2 receptors). We specifically evaluated whether these compounds affected 2 recently discovered proteins involved in controlling ras function: Shc, which is tyrosine‐phosphorylated by src and activated growth factor receptors, and Grb‐2, which mediates signal transduction from activated growth factor receptors through ras. We evaluated their effects on tyrosine phosphorylation of Shc, binding of Grb‐2 to Shc and MAP kinase activity. Both cell lines were inhibited in a dose‐dependent manner by each compound. This was accompanied by decreased Shc tyrosine phosphorylation, Shc's association with Grb‐2 and MAP kinase activity. Thus, tyrosine kinase inhibitors can inhibit proliferation of breast cancer cells, accompanied by inhibition of signal transduction steps potentially mediated through ras. Tyrosine kinase inhibitors might, therefore, be useful for the treatment of breast cancer. © 1996 Wiley‐Liss, Inc.